0515 GMT - The U.S. Treasury's announcement Wednesday of an increase in its buyback program appears to point to an attempt to calm nerves as the 30-year Treasury yields moved steadily towards 20-year highs, TwentyFour Asset Management's Eoin Walsh says in a note. "The timing of the move suggests the Trump administration is feeling the rate pressure, possibly with midterm elections on the horizon," the partner in portfolio management says. It may also be because there is no other help at hand: President Trump is doubling down on "crushing economic operations" on Iran, while the Federal Open Markets Committee minutes showed that many participants believed that hikes would be needed if the rate of inflation fails to decline, Walsh says.